Variable angle screws, plates and systems

ABSTRACT

The present disclosure relates, according to some embodiments, to orthopedic implantable device technology, and more specifically to variable angle implantable devices, systems, and methods.

This is a divisional application of U.S. application Ser. No.13/830,387, which was filed on Mar. 14, 2013 and is incorporated hereinby reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates, in some embodiments, to orthopedicimplantable device technology, and more specifically to variable angleimplantable devices, systems, and methods.

BACKGROUND

Bone plates and screws may be used to stabilize bones in the body of asubject (e.g., human, non-human animal). Plates may be secured to bonesusing screws that are directed inwardly through holes in the plates andinto underlying bone. While a screw may be inserted with itslongitudinal axis aligned with the axis of the hole through which itpasses, this angle may not be optimal in all circumstances. For example,an alternate insertion angle may be desired in light of the shape of theunderlying bone, the forces to which it is subjected, and/or the natureof the condition to be stabilized.

SUMMARY

Accordingly, a need has arisen for improved bone fixation devices andsystems that permit practitioners to select the angle at which thefixation member is inserted. The present disclosure relates, in someembodiments, to orthopedic implantable device technology, and morespecifically to variable and/or selectable angle implantable devices,systems, and methods. A fixation member angle may be assessed withrespect to a reference point on the fixation member (e.g., alongitudinal axis) and a reference point on a subject's bone, anassociated plate, and/or a longitudinal axis of a hole through which thefixation member is inserted.

The present disclosure relates, according to some embodiments, to avariable angle orthopedic plate. For example, a plate may comprise anupper surface, a bone facing surface, and/or at least one variable anglethrough hole between the upper surface and the bone facing surface. Insome embodiments, a through hole may have a generally cylindrical shapewith a central hole axis and/or may comprise a single continuous thread,the apex of which defines a central hole aperture of radius(r_(aperture)). A hole may comprise a thread trough defining a totalhole radius of (r_(hole)), according to some embodiments. A thread mayhave, in some embodiments, at least one indentation along its length,each indentation having a radius (r_(indent)), whereinr_(aperture)<r_(indent)<r_(hole). A variable angle hole may be operableto engage a threaded head of an orthopedic fastener at a first anglealigned with the central hole axis and at least one other angle (e.g.,0<α≤60°). A thread may comprise a plurality of indentations arranged inat least one column parallel or substantially parallel to the centralhole axis. For example, a thread may comprise a plurality ofindentations arranged in 2 columns, 3 columns, 4 columns, 5 columns, or6 columns, each parallel or substantially parallel to the central holeaxis and spaced around (e.g., uniformly spaced around) the central holeaxis. A thread, in some embodiments, may span the length of the holefrom the upper surface to the bone facing surface. According to someembodiments, a thread may further comprise one or more turns around thecircumference of the hole. According to some embodiments, an apertureradius (r_(aperture)) may be about 35% to about 98% r_(hole), and a holethread radius (r_(indent)) is about 36% to about 99% r_(hole). A platemay include a second hole (e.g., a fixed angle hole, a variable anglehole).

According to some embodiments, a variable angle orthopedic plate maycomprise a variable angle through hole comprising at least one threadspanning at least one turn (e.g., two turns, three turns, or more)around the circumference of the hole. In some embodiments, each turn maycomprise a first region having a maximum thread height (h_(max1)), asecond region having a maximum thread height (h_(max2)), and a thirdregion having a minimum thread height (h_(min3)) positioned between thefirst region and the second region, wherein h_(max1)>h_(min3),h_(max2)>h_(min3), and h_(min3)>0 for each turn independently. The thirdregions of each turn may be aligned in a column parallel orsubstantially parallel with the central hole axis. Each turn maycomprise, according to some embodiments, a fourth region having amaximum thread height (h_(max4)) and a fifth region having a minimumthread height (h_(min5)) positioned between the second region and thefourth region, wherein h_(max2)>h_(min5), h_(max4)>h_(min5), andh_(min5)>0, wherein the fifth regions of each turn are aligned in acolumn parallel or substantially parallel with the central hole axis. Insome embodiments, each turn may comprise a sixth region having a maximumthread height (h_(max6)) and a seventh region having a minimum threadheight (h_(min7)) positioned between the fourth region and the sixthregion, wherein h_(max4)>h_(min7), h_(max6)>h_(min7), and h_(min7)>0,wherein the seventh regions of each turn are aligned in a columnparallel or substantially parallel with the central hole axis. Each turnmay comprise a an eighth region having a maximum thread height(h_(max8)) and a ninth region having a minimum thread height (h_(min9))positioned between the sixth region and the eighth region, whereinh_(max6)>h_(min9), h_(max8)>h_(min9), and h_(min9)>0, wherein the ninthregions of each turn are aligned in a column parallel or substantiallyparallel with the central hole axis in some embodiments. Additionalregions of maxima and minima may be included in a thread according tosome embodiments. Thread regions of minimum height may be, in someembodiments, about equal (e.g., h_(min3)≈h_(min5)≈h_(min7)≈h_(min9)) toone another. Thread regions of maximum height may be, in someembodiments, about equal (e.g.,h_(max1)≈h_(max2)≈h_(max4)≈h_(max6)≈h_(max8)) to one another. Accordingto some embodiments, a thread may have a minimum thread height(h_(min3)) is about 1% to about 80% (e.g., about 5% to about 60%) ofmaximum thread height (h_(max1)).

The circumferential extent of regions of minimum hole thread heightand/or maximum hole thread height may be selected as desired someembodiments. The circumferential extent of each region may berepresented as c_(extent), wherein 0°<c_(extent1)+c_(extent2)+ . . .c_(extentN)≤360°, where N is the total number of regions of minimum andmaximum height. In some embodiments, the circumferential extent of theregions of maximum thread height (e.g., the first region, the secondregion, the fourth region, the sixth region, and/or the eighth region)may total, for example, more than 120°, more than 150°, more than 180°,more than 210°, and/or more than 240°. The circumferential extent of theregions of maximum thread height (e.g., the third region, the fifthregion, the seventh region, and/or the ninth region) may total, forexample, less than 120°, less than 150°, less than 180°, less than 210°,and/or less than 240°.

A thread may comprise, according to some embodiments, any desiredtransition from one region to the next. For example, a transition may bestep-wise, graded, or smooth. An orthopedic plate may comprise onevariable angle hole and at least one other hole in some embodiments. Asecond hole may be any type of hole desired including, for example, afixed angle hole, a variable angle hole (e.g., like the first ordifferent), or a compression hole. A through hole may have any desiredsymmetric or asymmetric shape including, for example, generallycylindrical, hourglass, inverted hourglass, and others.

A hole thread minimum (e.g., each hole thread minimum) may be selected,in some embodiments, as a function of its adjacent thread maximum. Forexample, a hole thread minimum may be from about 1% to about 90% of theadjacent hole thread maxima, from about 5% to about 80% of the adjacentthread maxima, from about 10% to about 70% of the adjacent threadmaxima, and/or from about 20% to about 60% of the adjacent threadmaxima.

A variable angle orthopedic plate may comprise, according to someembodiments, a variable angle through hole comprising at least onethread spanning at least a first turn around the circumference of thehole, the first turn comprising a first region having a maximum threadheight (h_(max1-1)), a second region having a maximum thread height(h_(max1-2)), and a third region having a minimum thread height(h_(min1-3)) positioned between the first region and the second region,wherein h_(max1-1)>h_(min1-3), h_(max1-2)>h_(min1-3), and h_(min1-3)>0.In some embodiments, the regions of maximum thread height may beapproximately equal (e.g., h_(max1-1)≈h_(max1-2)). A minimum threadheight (h_(min1-3)) may be about 1% to about 80% of maximum threadheight (h_(max1-1)) in some embodiments. A thread may further comprise,according to some embodiments, a second turn around the circumference ofthe hole. A second turn may comprise, for example, a first region havinga maximum thread height (h_(max2-1)), a second region having a maximumthread height (h_(max2-2)), and a third region having a minimum threadheight (h_(min2-3)) positioned between the first region and the secondregion, wherein h_(max2-1)>h_(min2-3), h_(max2-2)>h_(min2-3), andh_(min2-3)>0, wherein the third region of the first turn and the thirdregion of the second turn are aligned in a column parallel orsubstantially parallel with the central hole axis.

The present disclosure relates, in some embodiments, to a variable angleorthopedic fastener (e.g., screw). A variable angle orthopedic fastener(e.g., screw) may comprise, for example, a threaded shank having anupper end and a tip and a head fixed to the upper end of the shank. Ahead may comprise a core (e.g., a generally cylindrical core) of radius(r_(core)) and with a longitudinal axis, a single continuous threadencircling the core, the apex of which defines an outer periphery ofradius (r_(head)); and/or a thread trough. A thread may have, in someembodiments, at least one indentation along its length, each indentationhaving a radius (r_(head-indent)), whereinr_(core)<r_(head-indent)<r_(head). A variable angle fastener (e.g.,screw) may be operable to engage a threaded hole of an orthopedic plateat a first angle aligned with the central hole axis and at least oneother angle in some embodiments. In some embodiments, a thread maycomprise a plurality of indentations arranged in at least one column(e.g., 2, 3, 4, 5, 6 or more columns), with each column optionallyparallel or substantially parallel to the longitudinal axis. Columns maybe spaced (e.g., evenly spaced) around the longitudinal axis. A headthread may encircle the full length of a fastener (e.g., screw) head oronly a portion of a head (e.g., where a screw head cap is present). Thehead thread lead, pitch, length, height, width may be selected asdesired. For example, a thread may be long enough to encircle the headin one or more turns (e.g., 2, 3, 4 turns or more) in some embodiments.A head and/or thread may be sized so r_(core) is about 25% to about 98%r_(head), and r_(head-indent) is about 26% to about 99% r_(head) orr_(core) is about 25% to about 75% r_(head), and r_(head-indent) isabout 26% to about 90% r_(head).

According to some embodiments, a variable angle orthopedic fastener(e.g., screw) may comprise a threaded shank and a head fixed to theshank optionally defining a longitudinal screw axis. A head maycomprise, for example, at least one thread spanning at least one turn(e.g., two turns, three turns, or more) around the circumference of thehead. Each turn of a thread may comprise a first region having a maximumthread height (h_(max1)), a second region having a maximum thread height(h_(max2)), and/or a third region having a minimum thread height(h_(min3)) positioned between the first region and the second region,wherein h_(max1)>h_(min3), h_(max2)>h_(min3), and h_(min3)>0 for eachturn independently. In some embodiments, the third regions of each turnare aligned in a column parallel or substantially parallel with thelongitudinal axis of the fastener. Each turn may comprise, according tosome embodiments, a fourth region having a maximum thread height(h_(max4)) and a fifth region having a minimum thread height (h_(min5))positioned between the second region and the fourth region, whereinh_(max2)>h_(min5), h_(max4)>h_(min5), and h_(min5)>0, wherein the fifthregions of each turn are aligned in a column parallel or substantiallyparallel with the longitudinal axis. In some embodiments, each turn maycomprise a sixth region having a maximum thread height (h_(max6)) and aseventh region having a minimum thread height (h_(min7)) positionedbetween the fourth region and the sixth region, whereinh_(max4)>h_(min7), h_(max6)>h_(min7), and h_(min7)>0, wherein theseventh regions of each turn are aligned in a column parallel orsubstantially parallel with the longitudinal axis. Each turn maycomprise a an eighth region having a maximum thread height (h_(max8))and a ninth region having a minimum thread height (h_(min9)) positionedbetween the sixth region and the eighth region, whereinh_(max6)>h_(min9), h_(max8)>h_(min9), and h_(min9)>0, wherein the ninthregions of each turn are aligned in a column parallel or substantiallyparallel with the longitudinal axis in some embodiments. Thread regionsof minimum height may be, in some embodiments, about equal (e.g.,h_(min3)≈h_(min5)≈h_(min7)=h_(min9)) to one another. Thread regions ofmaximum height may be, in some embodiments, about equal (e.g.,h_(max)≈h_(max2)≈h_(max4)≈h_(max6)≈h_(max8)) to one another. Accordingto some embodiments, a thread may have a minimum thread height(h_(min3)) is about 1% to about 80% (e.g., about 5% to about 60%) ofmaximum thread height (h_(max1)).

The circumferential extent of regions of minimum head thread heightand/or maximum head thread height may be selected as desired someembodiments. The circumferential extent of each region may berepresented as c_(extent), wherein 0°<c_(extent1)+c_(extent2)+ . . .c_(extentN)≤360°, where N is the total number of regions of minimum andmaximum height. In some embodiments, the circumferential extent of theregions of maximum thread height (e.g., the first region, the secondregion, the fourth region, the sixth region, and/or the eighth region)may total, for example, more than 120°, more than 150°, more than 180°,more than 210°, and/or more than 240°. The circumferential extent of theregions of maximum thread height (e.g., the third region, the fifthregion, the seventh region, and/or the ninth region) may total, forexample, less than 120°, less than 150°, less than 180°, less than 210°,and/or less than 240°.

A head thread may comprise, according to some embodiments, any desiredtransition from one region to the next. For example, a transition may bestep-wise, graded, or smooth. A head thread minimum (e.g., each headthread minimum) may be selected, in some embodiments, as a function ofits adjacent thread maximum. For example, a head thread minimum may befrom about 1% to about 90% of the adjacent head thread maxima, fromabout 5% to about 80% of the adjacent thread maxima, from about 10% toabout 70% of the adjacent thread maxima, and/or from about 20% to about60% of the adjacent thread maxima. A fastener head may have any desiredsymmetric or asymmetric shape including, for example, generallycylindrical, hourglass, inverted hourglass, spherical, and others.

A variable angle orthopedic fastener (e.g., screw) may comprise,according to some embodiments, a variable angle through head comprisingat least one thread spanning at least a first turn around thecircumference of the head, the first turn comprising a first regionhaving a maximum thread height (h_(max1-1)), a second region having amaximum thread height (h_(max1-2)), and a third region having a minimumthread height (h_(min1-3)) positioned between the first region and thesecond region, wherein h_(max1-1)>h_(min1-3), h_(max1-2)>h_(min1-3), andh_(min1-3)>0. In some embodiments, the regions of maximum thread heightmay be approximately equal (e.g., h_(max1-1)≈h_(max1-2)). A minimumthread height (h_(min1-3)) may be about 1% to about 80% of maximumthread height (h_(max1-1)) in some embodiments. A thread may furthercomprise, according to some embodiments, a second turn around thecircumference of the head. A second turn may comprise, for example, afirst region having a maximum thread height (h_(max2-1)), a secondregion having a maximum thread height (h_(max2-2)), and a third regionhaving a minimum thread height (h_(min2-3)) positioned between the firstregion and the second region, wherein h_(max2-1)>h_(min2-3),h_(max2-2)>h_(min2-3), and h_(min2-3)>0, wherein the third region of thefirst turn and the third region of the second turn are aligned in acolumn parallel or substantially parallel with the longitudinal axis.

The present disclosure relates, in some embodiments, to variable angleorthopedic systems. For example, a system may comprise an orthopedicplate selected from a fixed angle plate and a variable angle plate andan orthopedic fastener (e.g., screw) selected from a fixed anglefastener (e.g., screw) and a variable angle fastener (e.g., screw). Afixed angle plate may comprise an upper surface, a bone facing surface,and one or more holes between the upper surface and the bone facingsurface, each hole having a generally cylindrical shape with a centralhole axis and comprising a single continuous thread, the apex of whichdefines a central hole aperture of constant radius(r_(hole-aperture-constant)), and a thread trough defining a constanttotal hole radius of (r_(hole-constant)). A variable angle plateoptionally may be selected from any variable angle plate disclosedherein. For example, a variable angle plate may comprise an uppersurface, a bone facing surface, and at least one variable angle throughhole between the upper surface and the bone facing surface, the holehaving a generally cylindrical shape with a central hole axis andcomprising a single continuous thread, the apex of which defines acentral hole aperture of radius (r_(hole-aperture)), and a thread troughdefining a total hole radius of (r_(hole)), wherein the thread has atleast one indentation along its length, each indentation having a radius(r_(hole-indent)), wherein r_(aperture)<r_(hole-indent)<r_(hole). Afixed angle fastener (e.g., screw) may comprise a threaded shank and ahead fixed to the shank, the head comprising a generally cylindricalcore of constant radius (r_(head-core-constant)) and with a longitudinalaxis, a single continuous thread encircling the core, the apex of whichdefines an outer periphery of constant radius (r_(head-constant)), and athread trough. A variable angle fastener optionally may be selected fromany variable angle fastener disclosed herein. For example, a variableangle fastener may comprise a threaded shank and a head fixed to theshank, the head comprising a generally cylindrical core of radius(r_(head-core)) and with a longitudinal axis, a single continuous threadencircling the core, the apex of which defines an outer periphery ofradius (r_(head)), and a thread trough, wherein the thread has at leastone indentation along its length, each indentation having a radius(r_(head-indent)), wherein r_(core)<r_(head-indent)<r_(head). Accordingto some embodiments, a system includes at least one variable angledevice selected from a variable angle plate and a variable anglefastener (e.g., screw). For example, a system may include a variableangle orthopedic plate having a plurality of hole thread indentationsarranged in at least one column (e.g., 2, 3, 4, 5, 6 or more columns),each column parallel or substantially parallel to the central hole axis.A variable angle plate may have a variable angle hole aperture radiusr_(hole-aperture) of about 35% to about 98% r_(hole), and an indentradius r_(hole-indent) of about 36% to about 99% r_(hole). For example,a system may include a variable angle orthopedic fastener (e.g., screw)having a plurality of head thread indentations arranged in at least onecolumn (e.g., 2, 3, 4, 5, 6 or more columns), each column parallel orsubstantially parallel to the longitudinal axis of the head thread. Avariable angle fastener may have a variable angle screw head core radiusr_(head-core) is about 25% to about 98% r_(head), and screw headindentation radius r_(head-indent) is about 26% to about 99% r_(head).In some embodiments, a system may include both a variable angle plateand a variable angle fastener (e.g., screw).

A variable angle orthopedic system may comprise, in some embodiments, atleast one fixed angle fastener defining a longitudinal axis andcomprising a threaded head, and a threaded shank fixed to the head; andan orthopedic plate comprising at least one through hole defining acentral hole axis, and at least one means for receiving the head of thefixed angle fastener in the at least one hole at a 0° angle between thecentral hole axis and the longitudinal axis and at least one other angleα (e.g., 0<α≤30°, 0<α≤40°, 0<α≤50°). According to some embodiments, avariable angle orthopedic system may comprise a fixed angle platecomprising one or more holes, each hole defining a central hole axis andcomprising at least one thread and a variable angle fastener defining alongitudinal axis and comprising a threaded head, a threaded shank fixedto the head, and a means for inserting the head in the at least one holeat a 0° angle between the central hole axis and the longitudinal axisand at least one other angle α (e.g., 0<α≤30°, 0<α≤40°, 0<α≤50°).

The present disclosure relates, in some embodiments, to methods formaking a variable angle orthopedic plate. Methods for making a variableangle orthopedic plate may comprise, for example, providing a platecomprising an upper surface and a bone facing surface, forming a throughhole (e.g., having a generally cylindrical shape) between the uppersurface and the bone facing surface, forming at least one threadencircling the circumference of the hole at least once, the thread apexdefining a central hole aperture of radius (r_(aperture)), forming atleast one trough encircling the circumference of the hole at least once,the thread trough defining a total hole radius of (r_(hole)), and/orforming at least one indentation in each of the at least one thread,each indentation having a radius (r_(indent)), whereinr_(aperture)<r_(indent)<r_(hole). Forming a hole may comprise, in someembodiments, drilling, boring, perforating, puncturing, piercing,punching or other means for creating or enlarging an opening in amaterial (e.g., a plate). According to some embodiments, forming atleast one thread may comprise tapping, cutting (e.g., die cutting),grinding, milling, lapping, rolling, casting, molding, printing, andother means for creating a thread in a hole. Forming indentations (e.g.,1, 2, 3, 4, 5, 6 or more indentations) in each of the at least onethreads may include cutting (e.g., die cutting), milling, grinding,knurling, pressing, bending, and other means for reshaping and/orremoving at least a portion of a thread, in some embodiments. Holethread indentations may be spaced apart (e.g., evenly spaced apart) fromone or more other indentations and/or arranged in columns (e.g., wheretwo or more turns of threading are present).

The present disclosure relates, in some embodiments, methods for makinga variable angle orthopedic fastener. Methods may include, for example,(a) providing a fastener blank (e.g., having a generally cylindricalshape) that defines a longitudinal axis and comprises a proximal end anda distal end, (b) forming at least one head thread and trough encirclingthe circumference of the proximal end of the fastener blank at leastonce, the apex of each head thread defining an outer periphery of radius(r_(head)) and the trough of each thread defining a head core of radius(r_(core)), and/or (c) forming at least one indentation in each of theat least one threads, each indentation having a radius(r_(head-indent)), wherein r_(core)<r_(head-indent)<r_(head). In someembodiments, a method may further comprise forming at least one shankthread encircling the circumference of the distal end of the fastenerblank. According to some embodiments, forming a head thread and troughmay comprise tapping, cutting (e.g., die cutting), grinding, milling,lapping, rolling, casting, molding, printing, and other means forcreating a thread at or near one end of a fastener blank. Shank threadsmay be formed before, concurrently with, or after head thread formation.Forming indentations (e.g., 1, 2, 3, 4, 5, 6 or more indentations) ineach of the at least one threads may include cutting (e.g., diecutting), milling, grinding, knurling, pressing, bending, and othermeans for reshaping and/or removing at least a portion of a thread, insome embodiments. Head thread indentations may be spaced apart (e.g.,evenly spaced apart) from one or more other indentations and/or arrangedin columns (e.g., where two or more turns of threading are present).

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments of the disclosure may be understood by referring, inpart, to the present disclosure and the accompanying drawings, wherein:

FIG. 1A illustrates a perspective view of a plate having a variableangle hole according to a specific example embodiment of the disclosure;

FIG. 1B illustrates a cut-away view of the plate shown in FIG. 1A alonga section plane through the thickest portion of the hole threads;

FIG. 1C illustrates a cut-away view of the plate shown in FIG. 1A alonga section plane through the shallowest portion of the hole threads;

FIG. 1D illustrates a top view of the plate shown in FIG. 1A;

FIG. 1E illustrates a section view of the plate and screw shown in FIG.1D along section line 1E-1E;

FIG. 1F illustrates a section view of the plate and screw shown in FIG.1D along section line 1F-1F;

FIG. 2 illustrates a side view of a screw for insertion in a variableangle hole according to a specific example embodiment of the disclosure;

FIG. 3A illustrates a cut-away view of a plate like the one shown inFIG. 1 with a screw like the one shown in FIG. 2 inserted;

FIG. 3B illustrates a top view of the plate with an inserted screw shownin FIG. 3A;

FIG. 3C illustrates a section view of the plate and screw shown in FIG.3B along section line 3C-3C;

FIG. 3D illustrates a section view of the plate and screw shown in FIG.3B along section line 3D-3D;

FIG. 3E illustrates a top view of the plate and screw shown in FIG. 3A;

FIG. 3F illustrates a section view of the plate shown in FIG. 3E alongsection line 3F-3F;

FIG. 4A illustrates a top view of a plate having a variable angle holeaccording to a specific example embodiment of the disclosure;

FIG. 4B illustrates a cut-away view of the plate shown in FIG. 4A alonga section plane through the thickest portion of the hole threads;

FIG. 4C illustrates a section view of the plate shown in FIG. 4A withthe screw shown in FIG. 2 inserted;

FIG. 5A illustrates a top view of a plate having a variable angle holeaccording to a specific example embodiment of the disclosure;

FIG. 5B illustrates a cut-away view of the plate shown in FIG. 5A alonga section plane through the thickest portion of the hole threads;

FIG. 5C illustrates a section view of the plate shown in FIG. 5A with ascrew like the one shown in FIG. 2 inserted;

FIG. 6A illustrates a perspective view of a screw for insertion in avariable angle hole according to a specific example embodiment of thedisclosure;

FIG. 6B illustrates a perspective view of a bone plate with a singlehole with a uniform thread

FIG. 6C illustrates a section view of the plate shown in FIG. 6B alongsection line 6C-6C;

FIG. 6D illustrates a section view (along section line 6C-6C) of thescrew shown in FIG. 6A inserted in the plate shown in FIG. 6B with itsaxis aligned with the hole axis according to a specific exampleembodiment of the disclosure;

FIG. 6E illustrates a section view (along section line 6C-6C) of thescrew shown in FIG. 6A inserted in the plate shown in FIG. 6B with itsaxis intersecting the hole axis according to a specific exampleembodiment of the disclosure;

FIG. 7 illustrates a section view of a screw like the one shown in FIG.6A inserted in a plate like the one shown in FIG. 1B with the head axisintersecting the hole axis according to a specific example embodiment ofthe disclosure;

FIG. 8A illustrates a top view of a screw for insertion in a variableangle hole according to a specific example embodiment of the disclosure;

FIG. 8B illustrates a side view of the screw shown in FIG. 8A;

FIG. 8C illustrates a perspective view of the screw shown in FIG. 8A;

FIG. 9 illustrates a perspective view of a plate having a variable anglehole according to a specific example embodiment of the disclosure;

FIG. 10A illustrates a perspective view of a screw for insertion in avariable angle hole according to a specific example embodiment of thedisclosure; and

FIG. 10B illustrates a side view of the screw shown in FIG. 10A.

Table 1 below includes the reference numerals used in this disclosure.The hundreds digits correspond to the figure in which the item appearswhile the tens and ones digits correspond to the particular itemindicated. Similar structures share matching tens and ones digits.

Reference Detail 0 System 5 10 Plate 11 Upper surface 12 Bone-facingsurface 15 20 Hole 21 Thread 22 Thread peak 23 Thread indent 24 Threadtrough 25 Inner surface 29 Axis 30 Screw 31 Head 32 Head cap 33 Headthread 34 Head thread peak 35 36 Head thread trough 37 Shank 38 Shankthread 39 Axis 40 Screw 41 Head 42 Head cap 43 Head thread 44 Headthread peak 45 Head thread indent 46 Head thread trough 47 Shank 48Shank thread 49 Axis 50 Hole 51 Thread 52 Trough 55 Lateral surface 59Axis

DETAILED DESCRIPTION

The present disclosure relates, in some embodiments, to orthopedicimplantable device technology, and more specifically to variable and/orselectable angle implantable devices, systems, and methods. For example,an angle of installing a fixation device into a matrix (e.g., bone) maybe varied as desired upon device manufacture, upon device installation,upon system manufacture, upon system assembly, upon system installation,and/or combinations thereof.

Bone Plates

According to some embodiments, the present disclosure relates toimplantable plates. An implantable plate may be of any size and shapedesired and/or appropriate for being secured to a bone of interest. Forexample, an implantable plate may comprise a generally flat or contouredbody having an upper surface and a bone-facing surface. An upper surfaceand/or a bone-facing surface may be generally planar in someembodiments. An upper surface and/or bone facing surface may beindependently and/or correspondingly contoured. A bone plate maycomprise and/or be made from any material suitable for implantation intothe body, including, for example, stainless steel, titanium, ceramic,PEEK, a polymeric material, a carbon fiber material, a compositematerial, and/or combinations thereof, according to some embodiments. Abone plate may permit at least partial load sharing between bones orbone sections that it connects. For example, a bone plate may permit atleast partially sharing weight across a bone graft site. It may bedesirable, in some embodiments, to permit some movement and/or load tobe born by bone (e.g., to facilitate healing). According to someembodiments, a bone plate may be strong enough to resist collapsingforces and/or abnormal angulation during the healing of a bone.

An implantable plate may be secured to a bone using any desired and/orappropriate fastener including, for example, nails, screws, rods, andcombinations thereof. It may be desirable, in some embodiments, for abone plate to be secure in its attachment to the bone (e.g., to resistand/or prevent migration of the implant or back out of the screws fromthe bone which could result in damage to the structures surrounding thebone, causing potentially severe complications). According to someembodiments, a bone plate may be any object configured to receive one ormore (e.g., at least two) bone screws. A bone plate may comprise, insome embodiments, a rigid and/or semi-rigid body with one or more (e.g.,at least two) through holes, each configured to receive a bone screw.

A through hole may have a generally cylindrical shape and/or compriseone or more indents and/or one or more protrusions (e.g., threads,thread segments, ridges, bulges, knobs). Each indent may be configuredto engage a thread or other protrusion from a bone screw assembly (e.g.,from a bone screw assembly head). For example, each indent present maybe positioned along the circumference (e.g., in a regular or irregularpattern if there is more than one indent) of a through hole. A hole mayinclude, for example, one or more threads (e.g., a single entry thread,a double entry thread). According to some embodiments, the presentdisclosure relates to bone plates having at least one through holehaving at least one thread. A hole, in some embodiments, may have anaperture radius (r_(aperture)) measured from the central hole axis tothe hole thread peak. According to some embodiments, a hole may have atotal radius (r_(hole)) measured from the central axis of the hole tothe trough of a hole thread. A hole may have a constant and/or asubstantially constant total radius (r_(hole)), in some embodiments,through its entire thickness from the upper surface to the lowersurface. A hole thread may have a thread height (h_(thread)) calculatedas the total radius (r_(hole)) less the aperture radius (r_(aperture))in some embodiments. A thread height (h_(thread)) may be greater thanzero along the entire length of the thread according to someembodiments.

An aperture radius (r_(aperture)) of a bone plate hole and/or a holethread height (h_(thread)) may be constant along a thread's full lengthin some embodiments. A radius (r_(aperture)) of a variable-angle boneplate hole thread and/or a hole thread height (h_(thread)) may varyalong the thread's length. For example, a radius (r_(aperture)) of avariable-angle bone plate hole thread may vary (e.g., oscillate) betweena maximum (r_(aperture-max)) and a minimum (r_(aperture-min)) value(e.g., stepwise, continuously variable). In some embodiments, aperturemaxima may be arranged at the same or substantially the same positionabout the central axis of a hole, forming an indent in the hole thread.A variable-angle hole may have from about 1 to about 6 indents.According to some embodiments, indents may be arranged in any desiredposition about the central axis of a hole. For example, indents may bearranged at regular intervals about the central axis of a hole. Inspecific example embodiments, a hole with n indents may have the indentspositioned about every 360°/n around the central axis of the hole. Forexample, a hole with 3 indents may have the indents positioned every360°/3=120° about the central axis of the hole (e.g., at about 0°, about120°, and about 240°).

A maximum radius (r_(aperture-max)) (indent) and/or a minimum radius(r_(aperture-min)) (thread peak) of a hole thread may be selected asdesired and/or required by the conditions of anticipated use accordingto some embodiments. Similarly, a maximum thread height (h_(thread-max))and/or a minimum thread height (h_(thread-min)) may be selected, in someembodiments, as desired and/or required by the conditions of anticipateduse.

A minimum thread height (h_(thread-min)) may be selected, in someembodiments, in relation to a maximum thread height (h_(thread-max)).For example, a minimum thread height (h_(thread-min)) may be from about0% up to (but not including) 100% of a maximum thread height (h_(t-max))(e.g., about 0%, about 1%, about 2%, about 3%, about 4%, about 5%, about6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%,about 20%, about 21%, about 22%, about 23%, about 24%, about 25%, about26%, about 27%, about 28%, about 29%, about 30%, about 31%, about 32%,about 33%, about 34%, about 35%, about 36%, about 37%, about 38%, about39%, about 40%, about 41%, about 42%, about 43%, about 44%, about 45%,about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%,about 59%, about 60%, about 61%, about 62% about 63%, bout 64%, about6%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%,about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%,about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%,about 98%, and/or about 99%).

A maximum aperture radius (r_(aperture-max)) of a hole and/or thedistance (d_(indent)) along a thread between two minima may be selectedwith respect to the height of a screw head thread (e.g., to afford spacefor a head thread to pass between two thread maxima). A minimum radius(r_(aperture-min)) and/or the distance (d_(peak)) along a thread betweentwo maxima may be selected with respect to the purchase desired and/orrequired with a screw head thread. A hole thread may vary along itslength such that only one minimum (e.g., local or global) is positionedbetween any two global maxima and/or only one maximum (e.g., local orglobal) is positioned between any two global minima in some embodiments.

Thread regions of interest may be defined by points (e.g., adjacentpoints) of maximum thread height, average thread height, minimum threadheight, inflection, or combinations thereof, according to someembodiments. For example, regions of maximum and/or minimum threadheight may be defined by adjacent points of average thread height and/orpoints of inflection. Regions of interest may be distinct and/or overlapone another. For example, regions of maximum thread height may bedefined by adjacent points of minimum thread height and regions ofminimum thread height may be defined by adjacent points of maximumthread height, such that the respective regions overlap. Regions ofmaximum thread height may be defined by adjacent intervening points ofaverage height and, accordingly be distinct from similarly definedregions of minimum thread height.

The circumferential extent of regions of minimum hole thread heightand/or maximum hole thread height may be selected, according to someembodiments, as desired. Considerations may include the nature (e.g.,fixed or variable angle), height, thickness, pitch, lead, and/or threadcount of a hole thread to be engaged. The circumferential extent of eachregion may be, in some embodiments, independent of one or more otherregions and/or co-dependent on one or more other regions. For example,the circumferential extent of regions of minimum thread height may allbe the same or substantially the same. The circumferential extent ofregions of maximum thread height may all be the same or substantiallythe same.

The circumferential extent of each region may be represented asc_(extent), wherein 0°<c_(extent1)+c_(extent2)+ . . . c_(extentN)≤360°,where N is the total number of regions of minimum and maximum height. Insome embodiments, the circumferential extent of each region may be0°<c_(extent)≤360°/N. Where n_(min) represents the number of regions ofminimum height in each turn, the circumferential extent of each regionof minimum height (or optionally all regions of minimum height) may be0°<c_(extent-min)≤30°, 0°<c_(extent-min)≤60°, 0°<c_(extent-min)≤90°,0°<c_(extent-min)≤120°, 0°<c_(extent-min)≤150°, 0°<c_(extent-min)≤180°,0°<c_(extent-min)≤210°, 0°<c_(extent-min)≤240°, 0°<c_(extent-min)≤270°,0°<c_(extent-min)≤300°, 0°<c_(extent-min)≤330°, 0°<c_(extent-min)≤360°,and/or 0°<c_(extent-min)≤360°/n_(min). Where n_(max) represents thenumber of regions of maximum height in each turn, the circumferentialextent of each region of maximum height (or optionally all regions ofmaximum height) may be 0°<c_(extent-max)≤30°, 0°<c_(extent-max)≤60°,0°<c_(extent-max)≤90°, 0°<c_(extent-max)≤120°, 0°<c_(extent-max)≤150°,0°<c_(extent-max)≤180°, 0°<c_(extent-max)≤210°, 0°<c_(extent-max)≤240°,0°<c_(extent-max)≤270°, 0°<c_(extent-max)≤300°, 0°<c_(extent-max)≤330°,0°<c_(extent-max)≤360°, and/or 0°<c_(extent-max)≤360°/n_(max).

In some embodiments, a maximum (r_(aperture-max)) may be less than orequal to the total radius of a hole (r_(hole)). An indent, accordingly,may be smooth and contiguous with the thread troughs(r_(aperture-max)=r_(hole)) or may be contoured (e.g., notched) withresidual head threading (r_(aperture-max)<r_(hole)).

A variable angle hole may include, in some embodiments, any number ofturns of a hole thread. For example, a variable angle hole may includeabout 2, about 3, about 4, about 5, or about 6 turns of a hole thread.Each turn may comprise the same number or a different number of indentsand/or peaks according to some embodiments. For example, the firstturn(s) and/or the last turn(s) may have fewer or no indents than theother turn(s). For example, the first turn(s) and/or the last turn(s)may have fewer peaks (e.g., just one peak) compared to other turn(s).According to some embodiments, each turn of a hole thread may compriseindents and/or peaks of the same or different dimensions compared toother turns of the thread. For example, the first turn(s) and/or thelast turn(s) may have shallower indents than the other turn(s). Eachturn (e.g., a first turn and/or a last turn) may have 0 to 8 indents.For example, the first turn(s) and/or the last turn(s) may have higherpeaks compared to other turn(s).

According to some embodiments, a hole thread having fewer, shallower, orno indents in the upper-most turn and/or lower-most turn may provideadditional purchase for an inserted screw. Where the upper-most turnand/or lower-most turn of a hole thread has fewer, shallower, or noindents, the additional purchase may contribute to stronger and/or moredurable fixation of the bone. A hole thread having fewer, shallower, orno indents in its upper-most turn and/or lower-most turn may govern(e.g., limit) the degree of angulation of an inserted screw.

Bone Screws

According to some embodiments, the present disclosure relates to bonescrews. A bone screw may have, according to some embodiments, a centrallongitudinal axis and comprise a bone screw shank and a bone screw head.A bone screw shank may be configured to be secured to a matrix (e.g.,bone). For example, a bone screw shank may comprise one or more threadsalong at least a portion of its length.

A head may or may not have the same geometry and/or radius as a shankportion. For example, it may have a shape other than generally cylindricand/or may have a larger or smaller radius as compared to, for example,the average radius of a shank portion, the minimum radius (e.g., sampledat or near the midpoint of a bone screw shank longitudinal axis), themaximum radius, or any other radial metric of the shank portion. A headmay comprise, in some embodiments, one or more surfaces configured toreceive a corresponding tool to fit (e.g., drive) a screw into position(e.g., screwed into and secured to a matrix). These one or more surfacesmay be positioned anywhere on a head including, for example, near thecenter of a head and/or on a head's circumference. A bone screw head mayhave a threaded portion and an unthreaded portion. For example, a bonescrew head may have a generally cylindrical shape with a top end and ashank end joined to the shank wherein a thread encircles a portionnearer the shank and an unthreaded head cap is positioned nearer the topend.

A bone screw may comprise, for example, a head having a head thread anda shank having a shank thread. A head thread, in some embodiments, mayhave a radius (r_(head)) measured from the longitudinal screw axis tothe head thread peak. A head cap may have a radius equal to or greaterthan the maximum thread head radius (r_(head)). A head thread may have athread height (h_(headthread)) calculated as the difference between thedistance from the longitudinal screw axis to the head thread peak andthe distance from the longitudinal screw axis to the head thread trough.

A radius (r_(head)) of a bone screw head thread may be constant alongits full length in some embodiments. A radius of a variable-angle bonescrew head thread (r_(head)) may vary along its length. For example, aradius of a variable-angle bone screw head thread (r_(head)) may vary(e.g., oscillate) between a maximum (r_(head-max)) and a minimum(r_(head-min)) value (e.g., stepwise, continuously variable). In someembodiments, thread minima may be arranged at the same or substantiallythe same position about the longitudinal axis of a screw, forming anindent. A variable-angle screw may have from about 1 to about 6 indents.According to some embodiments, indents may be arranged in any desiredposition about the longitudinal axis of a screw. For example, indentsmay be arranged at regular intervals about the longitudinal axis of ascrew. In specific example embodiments, a screw with n indents may havethe indents positioned about every 360°/n around the longitudinal axisof a screw. For example, a screw with 3 indents may have the indentspositioned every 360°/3=120° about the longitudinal axis of a screw(e.g., at about 0°, about 120°, and about 240°).

A maximum radius (r_(head-max)) and/or minimum radius (r_(head-min)) ofa head thread may be selected as desired and/or required by theconditions of anticipated use according to some embodiments. A minimumradius (r_(head-min)) may be selected, in some embodiments, in relationto a maximum head thread radius (r_(head-max)). For example, a minimumradius (r_(head-min)) may be from about 60% up to (but not including)100% of a maximum radius (r_(head-max)) (e.g., about 60%, about 61%,about 62%, about 63%, about 64%, about 65%, about 66%, about 67%, about68%, about 69%, 71% t 70%, about 71%, about 72%, about 73%, about 74%,about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%,about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about94%, about 95%, about 96%, about 97%, about 98%, and/or about 99%). Aminimum radius (r_(head-min)) of a head thread and/or the distance(d_(indent)) along a thread between two maxima may be selected withrespect to the height of a hole thread (e.g., to afford space for a holethread to pass between two thread maxima). A maximum radius(r_(head-max)) and/or the distance (d_(peak)) along a thread between twominima may be selected with respect to the purchase desired and/orrequired with a hole thread. A head thread may vary along its lengthsuch that only one minimum (e.g., local or global) is positioned betweenany two global maxima and/or only one maximum (e.g., local or global) ispositioned between any two global minima in some embodiments.

Thread regions of interest may be defined by points (e.g., adjacentpoints) of maximum thread height, average thread height, minimum threadheight, inflection, or combinations thereof, according to someembodiments. For example, regions of maximum and/or minimum threadheight may be defined by adjacent points of average thread height and/orpoints of inflection. Regions of interest may be distinct and/or overlapone another. For example, regions of maximum thread height may bedefined by adjacent points of minimum thread height and regions ofminimum thread height may be defined by adjacent points of maximumthread height, such that the respective regions overlap. Regions ofmaximum thread height may be defined by adjacent intervening points ofaverage height and, accordingly be distinct from similarly definedregions of minimum thread height.

According to some embodiments, the circumferential extent of regions ofminimum head thread height and/or maximum head thread height may beselected as desired. Considerations may include the nature (e.g., fixedor variable angle), height, thickness, pitch, lead, and/or thread countof a hole thread to be engaged. The circumferential extent of eachregion may be, in some embodiments, independent of one or more otherregions and/or co-dependent on one or more other regions. For example,the circumferential extent of regions of minimum thread height may allbe the same or substantially the same. The circumferential extent ofregions of maximum thread height may all be the same or substantiallythe same. The circumferential extent of each region may be representedas c_(extent), wherein 0°<c_(extent1)+c_(extent2)+ . . .c_(extentN)≤360°, where N is the total number of regions of minimum andmaximum height. In some embodiments, the circumferential extent of eachregion may be 0°<c_(extent)≤360°/N. Where n_(min) represents the numberof regions of minimum height in each turn, the circumferential extent ofeach region of minimum height (or optionally all regions of minimumheight) may be 0°<c_(extent-min)≤30°, 0°<c_(extent-min)≤600,0°<c_(extent-min)≤90°, 0°<c_(extent-min)≤120°, 0°<c_(extent-min)≤150°,0°<c_(extent-min)≤180°, 0°<c_(extent-min)≤210°, 0°<c_(extent-min)≤240°,0°<c_(extent-min)≤270°, 0°<c_(extent-min)≤300°, 0°<c_(extent-min)≤330°,0°<c_(extent-min)≤360°, and/or 0°<c_(extent-min)≤360°/n_(min). Wheren_(max) represents the number of regions of maximum height in each turn,the circumferential extent of each region of maximum height (oroptionally all regions of maximum height) may be 0°<c_(extent-max)≤30°,0°<c_(extent-max)≤60°, 0°<c_(extent-max)≤90°, 0°<c_(extent-max)≤120°,0°<c_(extent-max)≤150°, 0°<c_(extent-max)≤180°, 0°<c_(extent-max)≤210,0°<c_(extent-max)≤240, 0°<c_(extent-max)≤270°, 0°<c_(extent-max)≤300°,0°<c_(extent-max)≤330°, 0°<c_(extent-max)≤360°, and/or0°<c_(extent-max)≤360°/n_(max).

In some embodiments, a minimum (r_(head-min)) may be greater than orequal to the radius of a core (r_(core)) of a screw head (e.g., measuredfrom the longitudinal axis of the screw to the trough of a head thread).A head indent, accordingly, may be smooth and contiguous with a headcore (r_(head-min)=r_(core)) or may be contoured (e.g., notched) withresidual head threading (r_(head-min)>r_(core)).

A variable angle fastener may include, in some embodiments, any numberof turns of a head thread. For example, a variable angle fastener mayinclude about 2, about 3, about 4, about 5, or about 6 turns of a headthread. Each turn may comprise the same number or a different number ofindents and/or peaks according to some embodiments. For example, thefirst turn(s) and/or the last turn(s) may have fewer or no indents thanthe other turn(s). For example, the first turn(s) and/or the lastturn(s) may have fewer peaks (e.g., just one peak) compared to otherturn(s). According to some embodiments, each turn of a head thread maycomprise indents and/or peaks of the same or different dimensionscompared to other turns of the thread. For example, the first turn(s)and/or the last turn(s) may have shallower indents than the otherturn(s). Each turn (e.g., a first turn and/or a last turn) may have 0 to8 indents. For example, the first turn(s) and/or the last turn(s) mayhave higher peaks compared to other turn(s).

According to some embodiments, a head thread having fewer, shallower, orno indents in the upper-most and/or lower-most turn may provideadditional purchase with a hole into which it is inserted. Where theupper-most turn and/or lower-most turn of a head thread has fewer,shallower, or no indents, the additional purchase may contribute tostronger and/or more durable fixation of the bone. A head thread havingfewer, shallower, or no indents in its upper-most turn and/or lower-mostturn may govern (e.g., limit) the degree of angulation of an insertedscrew. A head thread having fewer, shallower, or no indents in itslower-most turn may be inserted at a desired angle with relative ease.

Bone Fixation Systems

According to some embodiments, the present disclosure relates to systemsfor securing bone(s). For example, a fixation system may comprise a bonescrew and a bone plate. Optionally, a fixation system may comprise, insome embodiments, a bone screw, a bone plate, a variable and/orselectable angle screw, a variable and/or selectable angle plate, and/orcombinations thereof.

According to some embodiments, a fixation system may be fastened to oneor more bones. For example, a fixation system may be fastened to asingle bone (e.g., across a fracture or break) or to two or more bones(e.g., vertebrae). A bone plate may comprise one or more apertures(e.g., from 1 to about 20 apertures). Some apertures (e.g., eachaperture) may receive a bone fasterner (e.g., bone screw), whichfastener may be fitted into a bone drill hole, for example, to fastenthe bone plate to bone.

Each member of a fixation system independently may comprise one or morematerials suitable for implantation in a subject (e.g., a human and/or anon-human animal). Each member of a fixation system independently maycomprise one or more materials capable of providing suitable structuraland/or mechanical strength and/or integrity. Examples of suitablematerials may include, without limitation, titanium, cobalt, chromium,stainless steel, alloys thereof, and/or combinations thereof. Examplesof suitable materials may include, without limitation, plastics, fibers(e.g., carbon fiber) and/or bioabsorbable materials. Each member of afixation system independently may comprise one or more one or moresurface coatings (e.g., for drug delivery, to promote healing, to aidinstallation, to resist infection, to increase and/or reduce frictionbetween components, and the like).

Variability and/or selectability may be assessed with respect to (a) theangle formed by the intersection of the plane of a plate hole and thecentral longitudinal axis of a screw inserted therethrough, (b) theangle formed by the intersection of the plane of a bone plate and thecentral longitudinal axis of a screw inserted therethrough, and/or (c)the angle formed by the intersection of the central hole axis and thecentral longitudinal axis of a screw inserted therethrough. Variabilityand/or selectability may arise from whether a variable-angle plate isused with or without a variable angle screw, whether a variable-anglescrew is used with or without a variable angle screw, the pitch of ahead thread, the number, breadth, and depth of head thread indents, thehitch of a hole thread, the number, breadth, and depth of hole threadindents present, and combinations thereof.

In some embodiments, a variable angle plate system comprising a plateand a fastener may accommodate insertion of the fastener in the plate ata first angle α₁ formed by the central hole axis and the longitudinalfastener axis and at least one additional angle α₂ formed by the centralhole axis and the longitudinal fastener axis. A variable angle α (e.g.,α₁ and/or α₂) may range from about 0° to about 60°, from about 0° toabout 50°, from about 0° to about 40°, and/or from about 0° to about 30°according to some embodiments. Insertion of a fastener at an anglenormal or substantially normal to a plate hole may comprise, in someembodiments, inserting the fastener such that the central hole axis andthe longitudinal fastener axis are co-linear. In some embodiments, avariable angle plate system may accommodate insertion of a fastener in ahole at a first angle normal to the plane of the hole and at least oneangle oblique to the plane of the hole.

Methods of Use

The present disclosure relates, according to some embodiments, to amethod of securing one or more bones (e.g., bone fixation). For example,a method may comprise installing a bone plate system having a variableangle plate and/or a variable angle screw in a subject. A method maycomprise, in some embodiments, drilling a hole, tapping the hole, andthreading a bone screw into a bone. A method may comprise installing aself-drilling screw without pre-drilling and/or without tappingaccording to some embodiments. A guide may be held next to or attachedto a plate in some embodiments. A drill may be inserted, according tosome embodiments, into the guide and the hole drilled into the bone. Aguide, if used, may be removed and a tap may be threaded through thehole (e.g., following the same or substantially the same angle as adrill hole. It may be desirable to proceed with caution, for example, toprevent the sharp edges of the tap from damaging surrounding tissues orin creating too large a tap hole by toggling the handle of the tap. Thisdamage may reduce the security of the screw bite into the bone and/orincrease the likelihood of screw pullout. After tapping, a screw may beguided at a proper angle into a hole that has been created. In someembodiments, inadvertent misalignment may reduce pullout strength and/ormay result in damage to surrounding nerves or arteries.

Installing a fastener (e.g., a screw) may include, in some embodiments,varying the angle of insertion (e.g., the central longitudinal axis ofthe inserted screw) such that is not aligned or parallel with thecentral hole axis. Installing a fastener (e.g., a screw) may include, insome embodiments, selecting an angle of insertion (e.g., the centrallongitudinal axis of the inserted screw) that is not aligned or parallelwith the central hole axis. Varying an insertion angle may includevarying and selecting an insertion angle. Selecting an insertion anglemay include varying and selecting an insertion angle.

In some embodiments, a method may comprise contacting a bone platesystem comprising at least one variable angle fastener with a bone ofsubject, inserting the fastener in the bone at an insertion angle thatis not aligned or parallel with the central hole axis, and/orcombinations thereof. For example, inserting may be optionally repeatedfor up to all of the fasteners in the bone plate system.

A method of bone fixation may be used to address (e.g., prevent, treat,ameliorate, ease, and/or relieve) one or more conditions and/or symptomsthereof. Conditions that may be addressed include, according to someembodiments, traumatic conditions, pathological conditions,developmental conditions, degenerative conditions, and/or combinationsthereof. For example, a method of bone fixation may be used to addressdegenerative disc disease, spondylolisthesis, a bone fracture or break,spinal stenosis, deformities (e.g., scoliosis, kyphosis and/orlordosis), tumor, pseudoartrosis, necrosis, a bulging or herniated disc,arthrodesis, and combinations thereof. In some embodiments, a method ofbone fixation may be applied to any bone(s) in a subject body. A methodmay be applied, for example, to a subject's foot, hand, clavicle, spine,humerous, radius, ulna, femur, tibia, fibula, and/or combinationsthereof. A healthcare professional exercising reasonable prudence andcare may determine which embodiment is most desirable for a particularsubject.

Methods of Manufacture

In some embodiments, the present disclosure relates to methods ofmanufacturing variable angle devices and/or systems. For example, avariable angle plate may be made by providing a plate with an uppersurface, a bone-facing surface, and at least one hole, tapping the atleast one hole to form at least one thread and at least one trough, andforming at least one column of indents in the thread. A column ofindentations may have a depth that leaves at least some residual threadsuch that the threading is reduced but not altogether eliminated in theindentations. Providing a plate with an upper surface, a bone-facingsurface, and at least one hole may include providing a plate with anupper surface and a bone-facing surface and drilling at least one holethrough the plate. Forming an indentation in a thread (e.g., a column ofindents) may include, according to some embodiments, grinding away aportion of a thread, for example, along one, two, three, four, five, orsix zones that are substantially parallel to the central axis of a hole.In some embodiments, a method of making a variable angle plate mayinclude deburring, smoothing, polishing and/or coating (e.g., a thread,an indentation, a hole, a plate) as desired and/or required.

Making a variable angle screw may comprise providing a blank, forming ahead and a shank on the blank to produce a variable angle screw blank,providing a purchase point on the head of the screw blank (e.g., a slot,a cross, or other feature that allows torque to be applied to thescrew), cutting (e.g., die cutting) threads into the head of the screwblank, cutting (e.g., die cutting) into the shank of the screw blank,and/or forming at least one column of indents in the head thread. Acolumn of head thread indentations may have a depth that leaves at leastsome residual thread such that the threading is reduced but notaltogether eliminated in the indentations. A method of making a variableangle screw may include, according to some embodiments, deburring,smoothing, polishing and/or coating (e.g., a thread, an indentation, ahead, a screw) as desired and/or required

Specific Example Embodiments

Specific example embodiments of a variable angle plate are illustratedin FIGS. 1A-1F. Variable angle plate 110 comprises an upper surface 111,a bone-facing surface 112, and at least one variable angle hole 120.Upper surface 111 and/or bone-facing surface 112 may be generally planarin some embodiments. Upper surface 111 and/or bone facing surface 112may be independently and/or correspondingly contoured. Variable anglehole 120 has a generally cylindrical shape with continuous thread 121and adjoining thread trough 125 around its circumference. Thread 121comprises four sets of thread peaks 122 and indents 123 spaced apart atregular intervals. FIG. 1B is a cut away view illustrating hole 120along a section plane that bisects thread 121 at its maximum height(h_(thread-max)). FIG. 1C is a cut away view illustrating hole 120 alonga section plane that bisects thread 121 at its minimum height(h_(thread-min)).

The distance from central hole axis 129 to thread peak 122 correspondsto the minimum aperture radius (r_(min)) and the distance from centralhole axis 129 to indent 123 corresponds to the maximum aperture radius(r_(max)) as shown in FIG. 1C. The distance from central hole axis 129to lateral surface 125 corresponds to the total hole radius (r_(hole)).Plate 110 may further comprise one or more additional holes. Eachadditional hole may independently be a variable angle hole, a fixedangle hole, a compression hole, an unthreaded hole (e.g., to receive anail), and combinations thereof.

FIG. 1D is a top view of hole 120 showing that peaks 122 and indents 123are uniform in each turn of thread 121. FIG. 1E is a section viewillustrating hole 120 along a section plane that bisects thread 121 atits maximum height (h_(thread-max)). FIG. 1F is a cut away viewillustrating hole 120 along a section plane that bisects thread 121 atits minimum height (h_(thread-min)).

A specific example embodiment of a bone screw is illustrated in FIG. 2.Bone screw 230 comprises head 231 and shank 237. As shown, head 231 hasa generally cylindrical shape and comprises an upper portion withuntreaded head cap 232 and a lower portion with head thread 233. Thread233 comprises thread peak 234 and thread trough 236. Thread peak 234 hasa radius (r_(head)) that is substantially the same as head cap 232 anddoes not vary along its length. Shank 237 has a generally cylindricalshape and comprises shank thread 238 encircling its length. The radiusof shank thread 238 is substantially smaller than the head thread radius(r_(head)). In some embodiments, head thread 233 and shank thread 238need not be distinct as shown.

Specific example embodiments of a variable-angle system are illustratedin FIGS. 3A-3F. Variable-angle system 300 comprises variable angle plate310 and bone screw 330. As shown, screw 330 may be inserted in hole 320such that longitudinal axis 339 of screw 330 aligns with central holeaxis 329 (FIGS. 3A-3D). Screw 330 may be inserted in hole 320 such thatlongitudinal axis 339 of screw 330 intersects central hole axis 329 andforms (non-zero) angle α (FIGS. 3E-3F). FIG. 3A is a cut away viewillustrating hole 320 and screw 330 along a section plane that bisectshole thread 321 at its maximum height (h_(thread-max)). Head thread 333engages hole thread 321 and shank 337 extends below lower surface 312 ofplate 310 where it may engage an underlying matrix (e.g., bone). FIG. 3Bis a top view of plate 310 with screw 330 inserted in hole 320. FIG. 3Cis a section view illustrating hole 320 along a section plane thatbisects hole thread 321 at its maximum height (h_(thread-max)). FIG. 3Dis a cut away view illustrating hole 320 along a section plane thatbisects hole thread 321 at its minimum height (h_(thread-min)). Asshown, head thread 333 engages thread peaks 322, but does not reachindents 323 or lateral surface 325. Head cap 332 may extend above uppersurface 311 as illustrated or may be seated in hole 320 such that it isflush with upper surface 332. For example, thread 321 may extend upwardfrom lower surface 312 through hole 320 to a point sufficiently short ofupper surface 311 to allow hole 320 to receive head cap 332.

FIG. 3E is a top view of plate 310 with screw 330 inserted in hole 320at an angle α. FIG. 3F is a section view illustrating hole 320 along asection plane that bisects hole thread 321 at its maximum height(h_(thread-max)). FIG. 3F further illustrates intersection of hole axis329 and head axis 339 to form an angle α. According to some embodiments,axes 329 and 339 may be skew. Projections of skew axes 329 and 339 on asingle plane (e.g., a plane parallel to either axis) may intersect toform an angle α.

Specific example embodiments of a variable angle plate are illustratedin FIGS. 4A-4C. Variable angle plate 410 comprises an upper surface 411,a lower surface 412, and at least one variable angle hole 420. Variableangle hole 420 has a generally cylindrical shape with continuous thread421 and adjoining thread trough 425 around its circumference. Thread 421comprises three sets of thread peaks 422 and indents 423 spaced apart atregular intervals. FIG. 4A is a top view of plate 410 with screw 430inserted in hole 420. FIG. 4B is a section view illustrating hole 420along a section plane that bisects hole thread 421 at an intermediateheight. FIG. 4C is a section view of system 400 comprising plate 410 andscrew 430 inserted in variable angle hole 420. As shown, hole axis 429intersects with head axis 439 to form an angle α.

Specific example embodiments of a variable angle plate are illustratedin FIGS. 5A-5C. Variable angle plate 510 comprises an upper surface 511,a lower surface 512, and at least one variable angle hole 520. Variableangle hole 520 has a generally cylindrical shape with continuous thread521 and adjoining thread trough 525 around its circumference. Thread 521comprises six sets of thread peaks 522 and indents 523 spaced apart atregular intervals. FIG. 5A is a top view of plate 510 with screw 530inserted in hole 520. FIG. 5B is a perspective view illustrating hole520 along a section plane that bisects hole thread 521 at its maximumheight (h_(thread-max)). FIG. 5C is a section view of system 500comprising plate 510 and screw 530 inserted in variable angle hole 520.As shown, hole axis 529 intersects with head axis 539 to form an angleα.

Specific example embodiments of a variable angle bone screw areillustrated in FIGS. 6A-6E. Variable angle screw 640 comprises head 641and shank 647. As shown, head 641 has a generally cylindrical shape andcomprises head thread 643 running from the upper end to the end thatjoins shank 647. Thread 643 comprises thread peak 644 and thread trough646. Thread peak 644 has a radius (r_(head)) that varies along itslength. Shank 647 has a generally cylindrical shape and comprises shankthread 648 encircling its length. The radius of shank thread 648 issubstantially smaller than the head thread radius (r_(head)). In someembodiments, head thread 643 and shank thread 648 need not be distinctas shown. Head thread 643 comprises four sets of thread peaks 644 andindents 645 spaced apart at regular intervals. FIG. 6A is a perspectiveview of variable angle screw 640 with its head portion 641 and shankportion 647. FIG. 6B is a perspective view of bone plate 610 having hole650. As shown, hole 650 comprises thread 651 and trough 652. FIG. 6C isa section view of bone plate 610. Thread 651 and trough 652, asillustrated, encircle hole 650 substantially uniformly. FIG. 6D is asection view of variable angle system 600, which comprises bone plate610 and screw 640. As shown, screw 640 may be inserted in hole 650 suchthat longitudinal axis 649 of screw 640 aligns with central hole axis659. Hole thread 651 engages head thread 643, but does not reach indents645 or lateral surface 655. Shank 647 extends below lower surface 612 ofplate 610 where it may engage an underlying matrix (e.g., bone). Thedistance from longitudinal screw axis 649 to thread peak 644 correspondsto the maximum radius (r_(head-max)) and the distance from longitudinalscrew axis 649 to indent 645 corresponds to the minimum radius(r_(head-min)) as shown in FIG. 6D. The minimum thread radius(r_(head-min)) is the same as the radius of the core of head 641. Thus,thread 643 is discontinuous in that it has zero thread height at indents645.

FIG. 6E is a section view illustrating system 600 with variable anglescrew 640 inserted in hole 650 such that head axis 649 intersectscentral hole axis 659 to form an angle α. According to some embodiments,axes 649 and 659 may be skew. Projections of skew axes 649 and 659 on asingle plane (e.g., a plane parallel to either axis) may intersect toform an angle α. Plate 610 may further comprise one or more additionalholes. Each additional hole may independently be a variable angle hole,a fixed angle hole, a compression hole, an unthreaded hole (e.g., toreceive a nail), and combinations thereof.

Specific example embodiments of a variable angle system are illustratedin FIG. 7. Variable angle system 700 comprises variable angle plate 710and variable angle screw 740. As shown, variable angle screw 740 isinserted in variable angle hole 720 with head axis 749 intersecting holeaxis 729 to form angle β. Indents 723 and indents 745 are aligned suchthat head thread peaks 744 engage hole thread peaks 722 but do not reachlateral surface 725.

Specific example embodiments of a variable angle screw are illustratedin FIGS. 8A-8C. Variable angle screw 840 comprises head 841 and shank847. As shown, head 841 has a generally cylindrical shape and compriseshead thread 843 running from the upper end to the end that joins shank847. Thread 843 comprises thread peak 844 and thread trough 846. Threadpeak 844 has a radius (r_(head)) that varies along its length. Shank 847has a generally cylindrical shape and comprises shank thread 848encircling its length. The radius of shank thread 848 is substantiallysmaller than the head thread radius (r_(head)). In some embodiments,head thread 843 and shank thread 848 need not be distinct as shown. Headthread 843 comprises four sets of thread peaks 844 and indents 845spaced apart at regular intervals. The minimum thread radius(r_(head-min)) is greater than the radius of the core of head 841. Thus,thread 843 is continuous in that it no point of zero thread height.

Specific example embodiments of a variable angle plate are illustratedin FIG. 9. Variable angle plate 910 comprises an upper surface 911, alower surface 912, and at least one variable angle hole 920. Variableangle hole 920 has a generally cylindrical shape with continuous thread921 and adjoining thread trough 925 around its circumference. Thread 921comprises four sets of thread peaks 922 and indents 923 spaced apart atregular intervals. As shown, the upper-most turn of thread 921 has noindents.

Specific example embodiments of a variable angle screw are illustratedin FIGS. 10A-10B. Variable angle screw 1040 comprises head 1041 andshank 1047. As shown, head 1041 has a generally cylindrical shape andcomprises head thread 1043 running from the upper end to the end thatjoins shank 1047. Thread 1043 comprises thread peak 1044 and threadtrough 1046. Head thread 1043 comprises four sets of thread peaks 844and indents 845 spaced apart at regular intervals, except that thelower-most turn of thread 1043 has no indents.

As will be understood by those skilled in the art who have the benefitof the instant disclosure, other equivalent or alternative variableangle devices, system, and methods can be envisioned without departingfrom the description contained herein. Accordingly, the manner ofcarrying out the disclosure as shown and described is to be construed asillustrative only.

Persons skilled in the art may make various changes in the shape, size,number, and/or arrangement of parts without departing from the scope ofthe instant disclosure. For example, the position and number offasteners, holes, threads, peaks, and/or indents may be varied. In someembodiments, variable angle bone plates, fixed angle bone plates,variable angle bone screws, fixed angle bone screws, and non-screwfasterers may be interchangeable. Interchageability may allow fixationto be custom adjusted (e.g., by allowing the practitioner to use themost appropriate fastening means). In addition, the size of a deviceand/or system may be scaled up (e.g., to be used for adult subjects) ordown (e.g., to be used for juvenile subjects) to suit the needs and/ordesires of a practitioner. Each disclosed method and method step may beperformed in association with any other disclosed method or method stepand in any order according to some embodiments. Where the verb “may”appears, it is intended to convey an optional and/or permissivecondition, but its use is not intended to suggest any lack ofoperability unless otherwise indicated. Persons skilled in the art maymake various changes in methods of preparing and using a composition,device, and/or system of the disclosure. For example, a composition,device, and/or system may be prepared and or used as appropriate foranimal and/or human use (e.g., with regard to sanitary, infectivity,safety, toxicity, biometric, and other considerations).

Also, where ranges have been provided, the disclosed endpoints may betreated as exact and/or approximations as desired or demanded by theparticular embodiment. Where the endpoints are approximate, the degreeof flexibility may vary in proportion to the order of magnitude of therange. For example, on one hand, a range endpoint of about 50 in thecontext of a range of about 5 to about 50 may include 50.5, but not 52.5or 55 and, on the other hand, a range endpoint of about 50 in thecontext of a range of about 0.5 to about 50 may include 55, but not 60or 75. In addition, it may be desirable, in some embodiments, to mix andmatch range endpoints. Also, in some embodiments, each figure disclosed(e.g., in one or more of the examples, tables, and/or drawings) may formthe basis of a range (e.g., depicted value +/−about 10%, depicted value+/−about 50%, depicted value +/−about 100%) and/or a range endpoint.With respect to the former, a value of 50 depicted in an example, table,and/or drawing may form the basis of a range of, for example, about 45to about 55, about 25 to about 100, and/or about 0 to about 100.

All or a portion of a device and/or system for bone fixation may beconfigured and arranged to be disposable, serviceable, interchangeable,and/or replaceable. These equivalents and alternatives along withobvious changes and modifications are intended to be included within thescope of the present disclosure. Accordingly, the foregoing disclosureis intended to be illustrative, but not limiting, of the scope of thedisclosure as illustrated by the appended claims.

The title, abstract, background, and headings are provided in compliancewith regulations and/or for the convenience of the reader. They includeno admissions as to the scope and content of prior art and nolimitations applicable to all disclosed embodiments.

What is claimed is:
 1. A variable angle orthopedic plate, the platecomprising: an upper surface; a bone facing surface; at least onevariable angle through hole between the upper surface and the bonefacing surface, the through hole defined by a wall having a generallycylindrical shape with a central hole axis with a constant total radiusfrom the upper surface to the bone facing surface, wherein the wallcomprises a single continuous thread, the apex of which defines acentral hole aperture of radius (r_(aperture)), and a thread troughdefining a total hole radius of (r_(hole)), wherein the thread has atleast one indentation along its length, each indentation having a radius(r_(indent)), wherein r_(aperture)<r_(indent)<r_(hole), and wherein thesurface of the wall defining the variable angle hole engages a threadedhead of an orthopedic fastener at a first angle aligned with the centralhole axis and at least one other angle measured between the central holeaxis and an axis of an orthopedic fastener.
 2. A variable angleorthopedic plate according to claim 1, wherein the at least oneindentation further comprises a plurality of indentations arranged in atleast one column parallel or substantially parallel to the central holeaxis.
 3. A variable angle orthopedic plate according to claim 2, whereinthe at least one column further comprises 2 columns, 3 columns, 4columns, 5 columns, or 6 columns, each parallel or substantiallyparallel to the central hole axis and spaced around the central holeaxis.
 4. A variable angle orthopedic plate according to claim 3, whereinspaced around the central hole axis further comprises spaced uniformlyaround the central hole axis.
 5. A variable angle orthopedic plateaccording to claim 1, wherein the thread spans the length of the holefrom the upper surface to the bone facing surface.
 6. A variable angleorthopedic plate according to claim 1, wherein the thread furthercomprises one or more turns around the circumference of the throughhole.
 7. A variable angle orthopedic plate according to claim 1, whereinr_(aperture) is about 35% to about 98% r_(hole), and r_(indent) is about36% to about 99% r_(hole).
 8. A variable angle orthopedic plateaccording to claim 1, wherein the plate further comprises a fixed anglehole.
 9. A variable angle orthopedic plate according to claim 1, whereinat least one variable angle hole further comprises a second variableangle through hole between the upper surface and the bone facingsurface, wherein the second variable angle through hole is like thefirst.
 10. A variable angle orthopedic plate, the plate comprising: avariable angle through hole between an upper surface of the plate and abone facing surface of the plate, the through hold defined by a wallhaving a generally cylindrical shape with a central hold axis with aconstant total radius from the upper surface to the bone facing surface,wherein the wall comprises at least one turn of one thread spanning atleast one turn around the circumference of the wall, each turncomprising: a first region having a maximum thread height (h_(max1)), asecond region having a maximum thread height (h_(max2)), and a thirdregion having a minimum thread height (h_(min3)) positioned between thefirst region and the second region, wherein h_(max1)>h_(min3),h_(max2)>h_(min3), and h_(min3)>0 for each turn independently, whereinthe third regions of each turn are aligned in a column parallel orsubstantially parallel with the central hole axis.
 11. A variable angleorthopedic plate according to claim 10, wherein each turn furthercomprises: a fourth region having a maximum thread height (h_(max4)),and a fifth region having a minimum thread height (h_(min5)) positionedbetween the second region and the fourth region, whereinh_(max2)>h_(min5), h_(max4)>h_(min5), and h_(min5)>0 wherein the fifthregions of each turn are aligned in a column parallel or substantiallyparallel with the central hole axis.
 12. A variable angle orthopedicplate according to claim 11, wherein each turn further comprises: asixth region having a maximum thread height (h_(max6)), and a seventhregion having a minimum thread height (h_(min7)) positioned between thefourth region and the sixth region, wherein h_(max4)>h_(min7),h_(max6)>h_(min7), and h_(min7)>0, wherein the seventh regions of eachturn are aligned in a column parallel or substantially parallel with thecentral hole axis.
 13. A variable angle orthopedic plate according toclaim 12, wherein each turn further comprises: an eighth region having amaximum thread height (h_(max8)), and a ninth region having a minimumthread height (h_(min9)) positioned between the sixth region and theeighth region, wherein h_(max6)>h_(min9), h_(max8)>h_(min9), andh_(min9)>0, wherein the ninth regions of each turn are aligned in acolumn parallel or substantially parallel with the central hole axis.14. A variable angle orthopedic plate according to claim 13, whereinh_(max1)≈h_(max2)≈h_(max4)≈h_(max6)≈h_(max8).
 15. A variable angleorthopedic plate according to claim 13, wherein the circumferentialextent of the first region, the second region, the fourth region and thesixth region total more than 180°, the circumferential extent of thethird region, the fifth region, and the seventh region total less than180°, and circumferential extent of the first, second, third, fourth,fifth, sixth, and seventh regions total 360° or less.
 16. A variableangle orthopedic plate according to claim 13, wherein thecircumferential extent of the first region, the second region, thefourth region and the sixth region total more than 210°, thecircumferential extent of the third region, the fifth region, and theseventh region total less than 150°, and circumferential extent of thefirst, second, third, fourth, fifth, sixth, and seventh regions total360° or less.
 17. A variable angle orthopedic plate according to claim13, wherein the thread further comprises step-wise transitions from oneregion to the next region, graded transitions from one region to thenext region, smooth transitions from one region to the next region orcombinations of said regions.
 18. A variable angle orthopedic plateaccording to claim 13, wherein h_(min3)≈h_(min5)≈h_(min7)≈h_(min9). 19.A variable angle orthopedic plate according to claim 18, whereinh_(max1)≈h_(max2)≈h_(max4)≈h_(max6)≈h_(max8).
 20. A variable angleorthopedic plate according to claim 19, wherein minimum thread height(h_(min3)) is about 1% to about 80% of maximum thread height (h_(max1)).21. A variable angle orthopedic plate according to claim 19, whereinminimum thread height (h_(min3)) is about 5% to about 60% of maximumthread height (h_(max1)).
 22. A variable angle orthopedic plateaccording to claim 10 further comprising a second through hole.
 23. Avariable angle orthopedic plate according to claim 22, wherein thesecond through hole is a variable angle through hole like the firstthrough hole.
 24. A variable angle orthopedic plate according to claim10, wherein the at least one thread spanning at least one turn aroundthe circumference of the hole further comprises at least two turnsaround the circumference of the hole.
 25. A variable angle orthopedicplate according to claim 24, wherein the at least two turns around thecircumference of the hole further comprise at least three turns aroundthe circumference of the hole.
 26. A variable angle orthopedic plateaccording to claim 10, wherein the variable angle through hole has agenerally cylindrical shape.
 27. A variable angle orthopedic plate, theplate comprising: a variable angle through hole between an upper surfaceof the plate and a bone facing surface of the plate, the through holedefined by a wall having a generally cylindrical shape with a centralhole axis with a constant total radius from the upper surface to thebone facing surface, wherein the wall comprises at least one turn of onethread spanning at least a first turn around the circumference of asurface of the plate body defining the hole, the first turn comprising:a first region having a maximum thread height (h_(max1-1)), a secondregion having a maximum thread height (h_(max1-2)), and a third regionhaving a minimum thread height (h_(min1-3)) positioned between the firstregion and the second region, wherein h_(max1-1)>h_(min1-3),h_(max1-2)>h_(min1-3), and h_(min1-3)>0.
 28. A variable angle orthopedicplate according to claim 27, wherein h_(max1-1)≈h_(max1-2).
 29. Avariable angle orthopedic plate according to claim 27, wherein minimumthread height (h_(min1-3)) is about 1% to about 80% of maximum threadheight (h_(max1-1)).
 30. A variable angle orthopedic plate according toclaim 27, wherein the at least one turn of one thread further comprisesa second turn around the circumference of a surface of the plate bodydefining the hole, the second turn comprising: a first region having amaximum thread height (h_(max2-1)), a second region having a maximumthread height (h_(max2-2)), and a third region having a minimum threadheight (h_(min2-3)) positioned between the first region and the secondregion, wherein h_(max2-1)>h_(min2-3), h_(max2-2)>h_(min2-3), andh_(min2-3)>0, wherein the third region of the first tum and the thirdregion of the second tum are aligned in a column parallel orsubstantially parallel with the central hole axis.
 31. A variable angleorthopedic system, the system comprising: (a) an orthopedic plateselected from the group consisting of: (1) a fixed angle platecomprising: an upper surface; a bone facing surface; and one or morethrough holes between the upper surface and the bone facing surface,each hole defined by a wall having a generally cylindrical shape with acentral hole axis with a constant total radius from the upper surface tothe bone facing surface, wherein the wall comprises a single continuousthread spanning at least one tum around the circumference of a surfaceof the plate body defining the hole, the apex of which defines a centralhole aperture of constant radius (r_(hole-aperture-constant)), and athread trough defining a constant total hole radius of(r_(hole-constant)); and (2) a variable angle plate comprising: an uppersurface; a bone facing surface; and at least one variable angle throughhole between the upper surface and the bone facing surface, the holehaving a generally cylindrical shape with a central hole axis andcomprising a single continuous thread spanning at least one tum aroundthe circumference of a surface of the plate body defining the hole, theapex of which defines a central hole aperture of radius(r_(hole-aperture)), and a thread trough defining a total hole radius of(r_(hole)), wherein the thread has at least one indentation along itslength, each indentation having a radius (r_(hole-indent)), whereinraperture<r_(hole-indent)<r_(hole); and (b) at least one orthopedicscrew selected from the group consisting of: (1) a fixed angle screwcomprising: a threaded shank; and a head fixed to the shank, the headcomprising: a generally cylindrical core of constant radius(r_(head-core-constant)) and with a longitudinal axis, a singlecontinuous thread encircling the core, the apex of which defines anouter periphery of constant radius (r_(head-constant)); and a threadtrough; and (2) a variable angle screw comprising: a threaded shank; anda head fixed to the shank, the head comprising: a generally cylindricalcore of radius (r_(head-core)) and with a longitudinal axis, a singlecontinuous thread encircling the core, the apex of which defines anouter periphery of radius (r_(head)); and a thread trough, wherein thethread has at least one indentation along its length, each indentationhaving a radius (r_(head-indent)), whereinr_(core)<r_(head-indent)<r_(head), wherein the system comprises at leastone variable angle device selected from the group consisting of thevariable angle plate and the variable angle screw.
 32. A variable angleorthopedic system according to claim 31, wherein the orthopedic platecomprises a variable angle orthopedic plate.
 33. A variable angleorthopedic system according to claim 32, wherein the at least one holethread indentation further comprises a plurality of hole threadindentations arranged in at least one column parallel or substantiallyparallel to the central hole axis.
 34. A variable angle orthopedicsystem according to claim 33, wherein the at least one column furthercomprises 2 columns, 3 columns, 4 columns, 5 columns, or 6 columns, eachparallel or substantially parallel to the central hole axis and spacedaround the central hole axis.
 35. A variable angle orthopedic systemaccording to claim 32, wherein r_(hole-aperture) is about 35% to about98% r_(hole), and r_(hole-indent) is about 36% to about 99% r_(hole).36. A variable angle orthopedic system according to claim 31, whereinthe at least one orthopedic screw comprises a variable angle orthopedicscrew.
 37. A variable angle orthopedic system according to claim 36,wherein the at least one head thread indentation further comprises aplurality of head thread indentations arranged in at least one columnparallel or substantially parallel to the longitudinal axis of the headthread.
 38. A variable angle orthopedic system according to claim 37,wherein the at least one column further comprises 2 columns, 3 columns,4 columns, 5 columns, or 6 columns, each parallel or substantiallyparallel to the longitudinal axis and spaced around the longitudinalaxis.
 39. A variable angle orthopedic system according to claim 36,wherein r_(head-core) is about 25% to about 98% r_(head), andr_(head-indent) is about 26% to about 99% r_(head).
 40. A variable angleorthopedic system according to claim 31, wherein the orthopedic platecomprises a variable angle orthopedic plate and the at least oneorthopedic screw comprises a variable angle orthopedic screw.
 41. Avariable angle orthopedic system, the system comprising: at least onefixed angle fastener defining a longitudinal axis and comprising athreaded head, and a threaded shank fixed to the head; and an orthopedicplate comprising: at least one through hole between an upper surface ofthe plate and a bone facing surface of the plate, the through holedefined by a wall having a generally cylindrical shape with a centralhole axis with a constant total radius from the upper surface to thebone facing surface, wherein the wall comprises; and at least one meansfor receiving the head of the fixed angle fastener in the at least onehole at a 0° angle between the central hole axis and the longitudinalaxis and at least one other angle a between the central hole and thelongitudinal axis.
 42. A variable angle orthopedic system according toclaim 41, wherein O<α<40°.
 43. A variable angle orthopedic system, thesystem comprising: a fixed angle plate comprising one or more holes,each hole positioned between an upper surface of the plate and a bonefacing surface of the plate, the hole defined by a wall having agenerally cylindrical shape with a central hole axis with a constanttotal radius from the upper surface to the bone facing surface, whereinthe wall comprises at least one thread; and a variable angle fastenerdefining a longitudinal axis and comprising: a threaded head; a threadedshank fixed to the head; and a means for inserting the head in the atleast one hole at a 0° angle between the central hole axis and thelongitudinal axis and at least one other angle a between the centralhole axis and the longitudinal axis.
 44. A variable angle orthopedicsystem according to claim 43, wherein O<α<40°.